Handheld consumer electronic devices such as smart phones, portable internet devices, portable music players, and hand held gaming devices often include some form of visual display, such as a flat screen video display or a touch screen display. Touch screens are displays which also have the ability to detect the location of touches within the display area. This allows the display to be used as an input device, removing the keyboard and/or the mouse as the primary input device for interacting with the display's content. Such displays can be attached to computers or, as terminals, to networks. Touch screens also have assisted in recent changes in the design of personal digital assistants (PDAs), satellite navigation and mobile phone devices, making these devices more user-friendly.
Touch screens have become commonplace since the invention of the electronic touch interface in 1971 by Dr. Samuel C. Hurst. They have become familiar on PDAs, smart phones, and portable internet devices where a stylus or fingers are used to manipulate a graphical user interface (GUI) and to enter data. The popularity of smart phones, PDAs, portable game consoles, and many types of information appliances is driving the demand for, and the acceptance of, touch screens.
Currently, most devices that incorporate the use of touch interfaces use only a single touch interface per device. Because only a single touch interface is used, the manipulation of virtual objects displayed on those devices is limited. With a single touch interface, only 2-dimensional manipulation of virtual objects may be performed intuitively.
It is within this context that embodiments of the present invention arise.